Range control of self propelled missile



-|2 E F BY INVENTOR. E L KLEIN ATTORNEYS E. L. KLEIN Filed Sept. 11,1959 RANGE CONTROL OF SELF PROPELLED MISSILE Aug. 4, 1964 United StatesPatent l 3 142,959 RANGE CONTROL OF SELF PRGPELLED MISSILE Eugene L.Klein, Alexandria, Va., assignor to Phillips Petroleum Company, acorporation of Delaware Filed Sept. 11, 1959, Ser. No. 839,441 9 Claims.(Q1. 60-356) This invention relates to control of distance of flight ofguided missiles. In one aspect it relates to apparatus for theregulation or control of the distance of flight of solid propellant,guided missiles.

It is often desirable to be able to control the flight range of a rocketor guided missile. One application for a range control system is intactical or ground support rockets or guided missiles, where closecontrol of range is required to place fire accurately and close tofriendly ground forces. Heretofore range of such missiles has beencontrolled by trajectory angle, or by use of air-fric tion drag fines.Such methods of range control have certain disadvantages, among them,the degree or extent of range distance provided.

I find that by varying the amount of propellant charge in a rocket therange of the rocket is adjusted for all distances up to the maximum forwhich the rocket was built. Heretofore, variation in the amount ofpropellant charge has been accomplished by adding to or substractingfrom the charge prior to firing, or by manufacturing a series of rocketswith specified propellant charges adjusted for predetermined distances.These latter methods have the disadvantages of lack of flexibility,undue multiplicity of stocks and inconvenience of adjustment.Furthermore, it is practically impossible to make changes in the amountof propellant charge in a missile at the time of use under rapid fireconditions.

An object of this invention is to provide a missile capable ofadjustment as regards distance of flight. Another object is to provide amissile which can be easily and quickly adjusted as regards distance offlight even under rapid fire conditions. Still other objects andadvantages of this invention will be realized upon reading the followingspecification and drawing, which repectively describes and illustratespreferred embodiments of my invention.

I accomplish these and other objects and advantages by providing arocket having a uniform charge for all rockets of a given type, thecharge being of such a nature that combustion is limited or regulated toa predetermined percentage of the total charge. A control means isprovided which can be quickly and definitely adjusted for regulating thepercentage of the charge to be fired thereby regulating the range of therocket. This adjusting of a flight regulating mechanism can be carriedout any time prior to the firing operation, preferably immediatelybefore the missile is fired.

In the drawing, FIGURE 1 is a longitudinal view, partly in section, ofone embodiment of apparatus of my invention.

FIGURE 2 is a perspective view of a portion of FIG- URE 1.

FIGURE 3 is a perspective view of an alternate embodiment of a portionof FIGURE 1.

, surface burning by known methods in such a manner that the burning ofone segment will not ignite any other segpropellant segment begins toburn.

3,142,959 Patented Aug. 4, 1964 ment of propellant. Broadly speaking, amechanism is provided for regulating the number of propellant segmentsto be burned during a given flight and by thus regulating the number ofpropellant segments to be burned, the range of the missile isdetermined.

In FIGURE 1 separate and individual propellant segments 12 are separatedfrom each other by short distances and the entire assembly of propellantsegments is housed within a conventional case 11. Reference numeral 13identifies the exhaust nozzle of the case while 33 identifies theforward or leading end of the missile. In case the missile contains anexplosive charge, it will be contained in this leading end 33. Thepropellant segments are covered with a layer of restrictive material 32in such a manner as to eliminate free surfaces of solid propellant andthereby prevent the burning of the propellant segments at undesiredsurfaces. Each propellant segment is provided with an igniter 14 whichpreferably is an electrical igniter. Connected at one terminal of eachigniter 14 is a separate wire 17. The wires 17 from the several igniterspass along the inner surface of the case 11 as a cable 18 toward theforward. end at which they are connected to a regulating mechanism. Theother terminal of each igniter can, if desired, be grounded or, ifdesired, wires 17a can be connected, leading to a common wire or cable19 which, in turn, leads toward the forward end of the missile. A sourceof electromotive force 20, such as a battery, is connected to wire 19and grounded at 26 so as to provide electromotive force for energizingthe igniters. In FIGURE 1 is illustrated, broadly, a range controlmechanism 15 which is operated by adjusting a knob or pointer 21 to anumber on a scale on the outer surface of the missile case, the numbersbeing the numbers corresponding to the propellant segments. For example,if it is desired to fire the missile for an in tended range of 5/7 ofits maximum distance, knob or pointer 21 would be set to number 5 on thescale, thus causing 5 propellant segments of the rocket to burnsuccessively thereby causing the rocket to travel 5/7 of its maximumdistance.

FIGURE 2 illustrates, in some detail, a contact mechanism disposedinside the rocket case immediately under the pointer 21. This interiorapparatus comprises a plate 16 having contact points numbered 1, 2, 3,4, 5, 6 and 7, as illustrated. In FIGURE 3 is shown knob or pointer 21for clarity reasons even though the pointer itself is actually outsidethe casing. A stop 22, also illustrated in FIGURE 3, is attached, asshown, to pointer 21 so that upon rotation of this pointer the stop alsorotates. As illustrated in FIGURE 3, when pointer 21 is pointing atcontact 5, stop 22 is approximately midway between contacts 5 and 6 insuch a manner that a contact arm 23,

which is connected with a timer 27 illustrated in FIG URE 3, upon makingelectrical contact with contact 5,

cannot move to contact 6 because of the position of the stop 22. At thetime of manufacture of this assembly, contact arm 23 is positioned onthe side of contact point 1 opposite from contact point 2, so thatcontact is not made with any of the numbered contact points. Uponstarting the mechanism, contact arm 23 starts rotation around the axisof knob 21 as the center in a manner similar to the hands of a clock.Contact arm 23 first makes electrical contact with contact point 1 atwhich time igniter 14 of the propellant segment nearest exhaust nozzle13 is activated and this propellant segment starts to burn. The timer isso constructed that by the time the first propellant segment isconsumed, the moving contact arm 23 makes electrical contact withcontact point 2 and the second Thus, all five of the propellant segmentsburn in succession in a manner just described.

In FIGURE 3 is illustrated a push button switch 31 which completes anelectrical circuit from a source of electromotive force, such as abattery 29, through switch 31 and wires 30 to the electrical clock timer27, this circuit being grounded at 26a. The movable contact arm 23rotates as the electrical timer operates thereby making successivecontacts with the several contact points.

Contact point 1, FIGURE 3, is connected with igniter 14 of the firstpropellant segment through a wire 17 with the circuit being completedthrough the igniter, return Wire 19, source of electromotive force 20,such as a battery, and wire 25, to another terminal of the apparatuswhich, in this case, is a spindle upon which knob or pointer 21 isplaced. Ground for this circuit is at 26.

The embodiments illustrated in FIGURES 1 and 3 comprise an electricaltimer mechanism which is started, as mentioned hereinbefore, by pressinga push button starter switch 31.

In FIGURE 2 as illustrated, an electrical firing mechanism is regulatedby a mechanical timer 27a. Mechanical timer 27a is powered by a turningkey 24 in a keyhole 24a in a manner similar to winding an ordinaryclock. Thus, upon giving key 24 a tumor two, the timing mechanism isstarted. In this embodiment wires leading to the several igniters 14 anda source of electromotive force for exciting the igniters are the sameas illustrated in FIGURES 1 and 3. A plate which contains the severalcontact points 1 to 7, inclusive, is identified by reference numeral16a. This plate contains the keyhole 24a through which the stem ofwinding key 24 extends. Contact 23 is grounded by way of a wire 25 toground 26 with a circuit being completed through battery 20 and thencethrough wire 19 to the igniters.

In FIGURE 4 is illustrated a different type of control mechanism forregulation of the number of propellant segments to be burned during agiven flight. In this embodiment the wires lead from a battery, notshown, to first igniter 14, that is, the igniter nearest nozzle 13 ofthe case, are the only ones connected to the battery. Other igniters 14in succession are ignited by the burning of the previous propellantsegment. Thus, in FIG- URE 4, as the propellant segment 12 nearestnozzle 13 nears the end of its burning, a fuse 42 is ignited and as thefuse burns toward igniter 14 of the next propellant segment, igniter 14,attached to this second propellant segment, is actuated and startsburning of this second propellant. Other and successive propellantsegments are ignited in the same way. In order to control the number ofpropellant segments to be burned in a given flight, a heavy cord 41 isprovided and extends through a small opening in case 11 and is tiedaround the fuse as illustrated. If, for example, it is desired to adjustthe missile of FIGURE 4 for a flight distance equivalent to the burningof one propellant segment, the first cord 41 is then pulled mechanicallyand this pulling breaks fuse 42; and with this fuse 42 broken and pulledout of place, the second propellant segment cannot be ignited from thefirst. In this same manner the missile of FIGURE 4 can be adjusted forany flight distance merely by pulling the proper fuse cord and breakingthe fuse following the last propellant segment desired to be burned.

In FIGURE is illustrated still another embodiment of control mechanismfor regulating the flight distance of such a missile. This embodiment issomewhat similar to that illustrated in FIGURE 4 in that pull cords 51are provided. In FIGURE 5, however, in place of merely breaking a fuse55, a knife blade is attached to the inner end of the pull cords in sucha manner that upon pulling a cord the knife cuts the fuse therebyrendering the fuse discontinuous. In this manner a fuse which is severedcannot excite the next successive igniter. In this figure wires 53 and54 lead to a source of electromotive force for igniting the firstigniter 14 while in FIGURE 4 wires 43 and 44 lead to a source ofelectromotive force for exciting the first igniter 14.

Therefore to control the range of a missile or rocket it 4 is merelynecessary to determine the number of segments of solid propellant to beburned and then, as in FIGURE 1, merely adjust knob or pointer 21 to theproper contact, or, as in FIGURES 4 and 5, pull the proper cord to severthe fuse leading from one propellant segment to the next.

In place of numerals 1, 2, 3, etc., being stamped on the outer surfaceof case 11, if desired, the range of the missile corresponding to thepropellant segments can be stamped on the case. Thus, if propellantsegment 1 would propel the missile 1,000 yards, then 1,000 could bestamped in place of numeral 1. In like manner the rangedistance can bestamped on the outer surfaces of case 11 of FIGURES 4 and 5,corresponding to the particular pull cords. In order that pull cords 41or 51 of FIGURES 4 and 5, respectively, are not inadvertently pulled,these cords can be taped or otherwise rendered inoperative until suchtime as it is desired to regulate the missile for flight. In case a tapesuch as an adhesive tape is employed, it is merely necessary to stripoff the tape and pull the proper cord.

Any suitable solid propellant can be used in making up the propellantsegment for use according to this invention. One suitable solidpropellant is one containing ammonium nitrate as an oxidant and arubbery material such as a copolymer of butadiene and a vinylpyridine orother substituted heterocyclic nitrogen base compound, which afterincorporation is cured by a quaternization reaction or a vulcanizationreaction. Such a solid propellant is fully disclosed in a copendingapplication by Mahan and Hutchinson, Serial No. 561,944, filed January27, 1956, now Patent No. 2,441,878.

A restricting material, that is, a material for restricting surfaceburning of solid propellant grains, is fully described in a copendingapplication by Hayrnes et al., Serial No. 708,330, filed January 10,1958, now Patent No. 2,995,091. e

A suitable restricting material, as disclosed in Serial No. 708,330,includes such materials as cellulose acetate, ethyl cellulose,butadiene-methyl vinylpyridine copolymer, .GR-S, rubbery compositionsfree from oxidizing agents and the like. These materials are sprayed on,brushed on or otherwise applied to the propellant surface to berestricted, and cured in case the composition is of a 'curable type. Incase a restricting material is not of the curable type, such as methylphenyl urea, it is dissolved in a solvent applied to the surface, andthe solvent allowed to evaporate.

In reference to FIGURE 5, an alternate embodiment of the knife bladeillustrated in the drawing is a large knife blade having a large surfacearea so that when the edge of the blade cuts the fuse, some portion ofthe blade remains between the severed ends as an ignition barrier.

While certain embodiments of the invention have been described forillustrative purposes, the invention obviously is not limited thereto.

"Dhat which is claimed is:

1. A rocket comprising, in combination, a plurality of solid propellantsegments having their surfaces completely restricted against surfaceburning disposed serially along a common axis, said propellant segmentsbeing solid cylinders and having their longitudinal axes positionedalong said common axis for successive burning, a case surrounding saidsegments, said case having a leading end as regards direction of traveland an exhaust nozzle at the other end, a separate igniter operatively'positioned on and against the propellant on the side of each propellantsegment facing said exhaust nozzle, means for exciting the igniternearest said exhaust nozzle, and

means for regulating a predetermined number of said propellant segmentsto be burned. V

2. A rocket comprising, in combination, a plurality of solid propellantsegments having their surfaces completely restricted against surfaceburning disposed serially along a common axis, said propellant segmentsbeing solid cylinders and having their longitudinal axes positionedalong said common axis for successive burning, a case surrounding saidsegments, said case having a leading end as regards direction of traveland an exhaust nozzle at the other end, a separate igniter operativelypositioned on and against the propellant on the side of each propellantsegment facing said exhaust nozzle, a plurality of electrical circuits,each circuit of said plurality of circuits containing one each of saidigniters, a source of electrical energy connected into said circuits, atimer, each circuit being in electrical communication with said timer, atimer stop, said timer being adapted to close a predetermined number ofcircuits beginning with the circuit containing the igniter closest tosaid exhaust nozzle, and said timer stop being adjustable to stop saidtimer after closing a predetermined number of said circuits.

3. The rocket of claim 2 wherein said timer is a mechanical timer.

4. The rocket of claim 2 wherein said timer is an electrical timer.

5. A rocket comprising, in combination, a plurality of solid propellantsegments having their surfaces completely restricted against surfaceburning disposed serially along a common axis, said propellant segmentsbeing solid cylinders and having their longitudinal axes positionedalong said common axis for successive burning, a case surrounding saidsegments, said case having a leading end as regards direction of traveland an exhaust nozzle at the other end, a separate igniter operativelypositioned on and against the propellant on the side of each propellantsegment facing said exhaust nozzle, a separate fuse connectingoperatively each pro pellant segment with the igniter on the nextsuccessive propellant segment beginning with the propellant segmentnearest said exhaust nozzle, and means for disconnecting each fuse fromthe propellant segment to which it is connected for burning only apredetermined number of propellant segments.

6. The rocket of claim 5 wherein said means is a separate cord attachedto each fuse and extending through said case and each cord being adaptedon manually pulling same at its outer extremity to rupture the fuse towhich it is attached. I 7. The rocket of claim 5 wherein said meanscomprises a separate cutter positioned operatively to cut each fuse, aseparate pull cord attached to each cutter and extend ing through saidcase, each pull cord being adapted on being pulled manually from theexterior of said case to move the cutter to which it is attached therebysevering a fuse.

8. In a rocket having a maximum range of travel, a system for regulatingthe distance of travel of said rocket for a predetermined distance up tosaid maximum range comprising, in combination, a plurality of solidcylindrical, solid propellant segments having their surfaces completelyrestricted against surface burning disposed serially along a common axisfor successive burning, a case surrounding said segments, said casehaving a leading end as regards direction of travel and an exhaustnozzle at the other end, a separate igniter operatively positioned onand against the propellant on the side of each segment facing saidexhaust nozzle, means for exciting each igniter in succession beginningwith the igniter closest to said exhaust nozzle, and stop means forterminating successive excitations of said igniters at a predeterminedpropellant segment whereby only a predetermined number of propellantsegments is ignited thereby regulating the travel distance of saidrocket.

9. In a rocket having a maximum range of travel, a system for regulatingthe distance of travel of said rocket for a predetermined distance up tosaid maximum range comprising, in combination, a plurality of solidcylindrical, solid propellant segments having their surfaces completelyrestricted against surface burning disposed serially along a common axisfor successive burning, a case surrounding said segments said casehaving a leading end as regards direction of travel and an exhaustnozzle at the other end, a separate igniter operatively positioned onand against the propellant on the side of each segment facing saidexhaust nozzle, a separate electrical circuit communicating with eachigniter for exciting same in succession beginning with the igniterclosest to said exhaust nozzle, a timer for closing each circuit in saidsuccession, an adjustable stop means, this latter means being adapted tobe set to regulate operation of said timer to permit closing of apredetermined number of said circuits for excitation of said number ofigniters for burning of said number of segments and to prevent closingof a number of said circuits equal to the number of propellant segmentsless said predetermined number of circuits, thereby failing to ignitethe number of segments whose igniter circuits are not closed and thusregulating the distance of travel of said rocket.

References Cited in the file of this patent UNITED STATES PATENTS1,191,299 Goodard July 18, 1916 2,114,214 Damblanc Apr. 12, 19382,856,851 Thomas Oct. 21, 1958 2,945,344 Hutchinson July 19, 19602,956,401 Kane Oct. 18, 1960 FOREIGN PATENTS 9,398 Great Britain June27, 1888

1. A ROCKET COMPRISING, IN COMBINATION, A PLURALITY OF SOLID PROPELLANTSEGMENTS HAVING THEIR SURFACES COMPLETELY RESTRICTED AGAINST SURFACEBURNING DISPOSED SERIALLY ALONG A COMMON AXIS, SAID PROPELLANT SEGMENTSBEING SOLID CYLINDERS AND HAVING THEIR LONGITUDINAL AXES POSITIONEDALONG SAID COMMON AXIS FOR SUCCESSIVE BURNING, A CASE SURROUNDING SAIDSEGMENTS, SAID CASE HAVING A LEADING END AS REGARDS DIRECTION OF TRAVELAND AN EXHAUST NOZZLE AT THE OTHER END, A SEPARATE IGNITER OPERATIVELYPOSITIONED ON AND AGAINST THE PROPELLANT ON THE SIDE OF EACH PROPELLANTSEGMENT FACING SAID EXHAUST NOZZLE, MEANS FOR EXCITING THE IGNITERNEAREST SAID EXHAUST NOZZLE, AND MEANS FOR REGULATING A PREDETERMINEDNUMBER OF SAID PROPELLANT SEGMENTS TO BE BURNED.